Crank grinding machine



May 19, 1953 H. E. BALSIGER ET AL 2,538,719

CRANK GRINDING MACHINE Filed Aug. 26, 1948 4 Sheets-Sheet l Smaentor hARaLp E. Bnusmee RALPH E. PRICE (Ittorueg May 19, 1953 H. E. BALSIGER ETAL 2,638,719

CRANK GRINDING MACHINE Filed Aug. 26, 1948 I 4 Sheets-Sheet 2 ImmentorI/HROLD BALs/GEE EMF 5. PRICE azfg y 9, 1953 H. E. BALSIGER ET AL CRANKGRINDING MACHINE 4 Sheets-Sheet 3 Filed Aug. 26, 1948 rllll w w a. Z 9 wy 1953 H. E. BALSIGER ET AL 2,638,719

CRANK GRINDING MACHINE Filed Augv 26, 1948 4 Sheets-Sheet 4 'Juuentar r'350 (Utorneg T Patented May 19, 1953 CRANK GRINDING MACHINE Harold E.Balsigcr, Waynesboro, Pa and Ralph E. Price, Highfield, Md., assignors.to Landis Tool Company, Waynesboro, Pa.

Application August 26, 1948,- Serial No. 46,336

25 Claims. (01. 51-72) This invention relates to grinding machines,particularly for grinding crankshafts or other Work pieces havingaxially spaced portions to be ground.

In any grinding operation a high degree of accuracy is dependent on twoand sometimes three things:

. -1. Accurate size control,

Accurate feed mechanism,

' 3. Accurate means for supporting the work piece, particularly ingrinding axially spaced surfaces on a work piece.

A fourth requirement might be the skillful use of all of these so as toget the best results.

We prefer to use a sizing device of the socalled pneumatic type, themost recent development of which is disclosed in co-pending applicationSer. No. 773,388, filed September 11, 1947. However, while this isprobably the most accurate sizing device available, accurate sizecontrol is dependent on an accurate feed mechanism. It was formerlythought that the, slower the finish feed, the more accurate the finalsize. This slow feed was also supposed to permit relief of deflection inthe work and in the machine. However, there was found to be a mechanicalor frictional limitation to extremely slow feeding movements beyondwhich it was impractical to It was found that by keeping the slow feedwithin a range not affected by these limitations that inaccuracy due tolack of uniformity of feed rate can be eliminated. In addition to this,the entire feeding movement is divided into a series of successive sizecontrolled reductions in feed rate. The purpose of. this is not toeliminate deflection entirely, but to reduce it to a minimum which canbe relieved during a brief size controlled spark out operation.

One of the principal obstacles to accuracy in any machining operation isdeflection or distortion. This may occur in varying degree in the work,in the machine itself, or in both. It is the result of resilience of thework piece and the machine. These parts, therefore, yield or deflectwhen forced together by the feeding mechanism. In the case of grinding,distortion or deflection of the work may be counteracted by use of aback rest. H 1

Deflection in machine parts may be compensated for by stopping thefeeding mechanism for the grinding wheel and permitting the deflectedparts and assemblies to relieve themselves and, in so doing, to providea spark out grinding operation. The term spark out may be defined as arelative feeding movement between a grinding wheel and a work pieceoccurring after the feed mechanism has stopped, which is due to therelief of stresses in the work or machine or both. These stresses arebuilt up during that portion of the grinding operation when the feedmechanism is operating. a

The current method of supporting crank pins during grinding is to use asingle steady rest mounted on the bed of the machine and in alignmentwith the grinding wheel. This rest moves by power into position againsta positive stop, usually as soon as the work has been ground true, andis held against said stop while the operator adjusts the position of theshoe or shoes as the work is reduced in size. The adjustment requiredfor each pin on a shaft is usually different due to unequal deflectionat various points on the shaft, and thus the steady rest must beadjusted differently for the grinding of each pin. Usually the finalincrement of stock is removed by using this adjustment to feed the workagainst the wheel. This takes quite a bit of time,

and uniformity of adjustment by the operator cannot be guaranteed.

We propose to use a separate steady rest for each crank pin. Each restwill be movable into work supporting position only when the pin which itis to support is in front of the grinding wheel. Eachrest will bepre-adjusted to the particular pin which it is to support; i. e. whenthe rest engages its positive stop, it is located to support thatparticular pinin finished size position. When moved into workingposition, the rest will engage the work continuously until it alsoengages a, positive stop. When the rest engages the stop, it isdeflecting work toward wheel by a small amount. As the. wheel feedsforward and the stock is removed, the work maintains contact with therest; and as the work diameter is reduced, the axis of the pin coincideswith the axis of rotation of the shaft. The adjustment of each restshould be such that, when the sizing device stops the grindingoperation, the rest still exerts enough pressure on the work to preventchatter. At the end of this operation which is controlled by the sizingdevice the work should be round and straight and about .0005

oversize.

The grinding operation will be stopped and the feed mechanism reseteither after a predetermined interval or by the sizing device when. the.0005 stock has been removed.

. It is, therefore, an object of this invention to provide a machine forgrinding crank shafts to closer limits than has been possible withprevious machines.

A further object is to provide a separate, accurately adjusted steadyrest for each of the pins of a crank shaft.

A further object is to interlock the control of the steady rest and thefeeding mechanism.

A further object is. toprevent movement of any steady rest except theone for the portion of th shaft in grinding position. I

In the drawings:

Fig. 1 is a partial plan view. I

Fig. 2 is an end elevation partly in section.

Fig. 3 is an end elevation to the steady operating mechanism partlyinsection.

Fig. 4 is a hydraulic diagram of a safety feature of the machine. I a 7Figure 5 is a sectional elevation showing the rest relation of work restparts in operative positiorn Figure 6 shows the same parts ininoperative position.

Figure '7 is a hydraulic and electrical. diagram.

The bed of the machine is indicated by numeralIIl; the workcarriageslidably mounted thereon, by the numeral H. Said carriage issupported on a V anda flat guide. Only the. flat guide I2 is shown. Saidcarriage may be moved manually or bypower by any of several welliznownmechanisms.

a The wheel base I'5is slidably mounted on bed to fo movement inadirection transversely of. the carriage movement. A grinding wheel I6 isrotatably mounted on said base and driven by a motor I! through a beltdrive not shown. Said wheel base is slidably mounted on an intermediateslide 20, whichv in turn is slidably mounted on bed 10.

Wheel feed The means for'moving wheel base toward and from the workconsists'of a hydraulic motor comprising a cylinder mounted on bed Ill,a piston 26 slidably mounted therein and having a piston rod 21connected to slide 2! through lug 28. The dash pot mechanism 31 forcontrolling the feed movement is well-known and will not be describedhere. A half nut 29 on slide 20- engages a feed screw 30 rotatablymounted in wheel base 15. Thus slide 20 and base IB-maybe moved a a unitor base I5 may be moved relative to slide 20 by rotating feed screw 30.

Means for rotating feed screw 30 consists of a sprocket secured to oneend of said screw, 2. chain 36 connecting said sprocket with anothersprocket 31 on shaft 38 in the up-perpart of the base I5. Also mountedon said shaft 38 is a gear 39 meshing with gear 40 on-handwheelshaft 4!.A handwheel 62 provides means for manually feeding base 55 along slide20.

Handwheel 42 may bepower actuated by means consisting of a cylinder 56'forming part of the housing 5| of said manual feedmechanism, having adouble-headed piston" 52 slidably mounted therein. Said piston consistsof two heads joined by a rack 53. Said rack engages a' pinion 54 onhandwheel shaft 4|. a

A limit-switch 60 on the underside of housing 5| is positioned to beactuated by a cam 62 0-11 handwheel 42. This switch, when actuated,controls the movement of piston 52 as willbe described later.

A work piece In in the form of a six throw crank shaft is rotatablysupported on carriage II in hydraulic clamping fixtures H and "I2 onheadstocks notshown. The details of the clamping fixtures and headstocksa well as other details of machine structure are similar to those shownin Patent 2,220,490, granted November 5, 1940.

Steady rest A separate steady rest member is provided for each of thesix crank pins on crank 10. Each steady rest consists of a main framemember 80, pivotally mounted in a base member 8| common to all sixrests. Hereafter, the numeral will be used in referring to the steadyrest as a unit. The movement of each rest toward the work piece islimited by a stop 82 located on base BI in the path of movement of saidframe 80. The work engaging member is preferably a hardened shoe 83,removably mounted on a support member 84.

Saidsupport member is slidably mounted in said frame 80 and may beadjusted by means of screw 85. A tail portion 86 on said frame isslotted at 8'! to permit engagement with a cooperating portion on anactuating'member to bedescribed later. A stub shaft 88 extends acrossthe slotted portion of said tail. Said shaft'has a shallow transverseslot 89 which is engaged by a latch 93 forming one side of a recess 91in said portion Q5.

Portion 95 is secured to the end of a piston rod H33 on piston IOI. Saidpiston is slidably mounted in cylinder I02, which in turn ispivotallymounted at Hi3 on a bracket I04 attached to bed it so they move inaccordance with the pivotal movement of the steady rest 80. Said pistonrod extends upwardly through an opening H15 in a splash guard I05, whichextends the entire length of the work piece. Across the inside of saidshield, a pair of longitudinally spaced bars III and III- are placed.The bars are so locatedthat the space between them is directly; in line'with the grinding wheel. Said'space is wide enough to permit the passagetheretln'ough of the knob on adjusting screw- 85. When the'rests are ininoperative position, said bars prevent movement of all except. the onein line with the grinding wheel.

On top of cylinder W2 is a plate I20 urged upwardly by springs 1'22!against adjustable stops in the form of headed screws I 22. When pistonIilI. moves to. bottom position, the portion 95. engages and depressessaid plate which in turn depresses a valve stem I25. As shown in Figure4, stem #25 is; part. of: valve 126 slidably mounted in housing I21; Aspring I28: holds. valve I26 in closed position.

Single control lever 7 Most of the functions of this machine arecontrolled by means of a single lever [30. The positions of said leverfor controlling said functions are indicated on a guide plate I31having, apair of parallel slots I'3-2-and I 33 joinedby a connectingslot I34. In the position shown in, slot E32, it controls the rotationand clamping of the work. In slot I 33 it controls the traverse movementof carriage I I.

As a safety feature, movement of lever I30 from slot I 32 to slot I33may be prevented by blocking the connecting slot I35 The means for doingthis consists of a plunger I35 in a bore I36 in ahousing I31 which mayor-may not be integral with plate I3I. Said plunger is ac-' mated by apiston I-3B slidably mounted in a cylinder I39 in housing I3 1. Theportion of plunger I35 adjacent piston- I 3$ is reduced in diametersothat fluid under constant pressure may bedirectedto. the rodend-ofcylinder I39.

Fluid underconstant pressurefromline I40 is directed throughline I4I tothe rod end of cylinder I39 and through line I42, a restriction [.43 andline I44 to the head of said cylinder. Line I45 connects line I44withvalve housing I21. When valve I26 is closed, fluid under the samepressure is directed to both sides of piston I38. Because of thedifference in area of the opposite sides of said piston, it moves to theright so that plunger I 35 is projected into connecting slot I34. Whenvalve I26 is opened, line I45 is connected to exhaust line I46. Pressureon the headend of; piston I38 is reduced to exhaust pressure.Restriction I43 prevents a similar reduction in pressure on the rod endof said piston which then moves to the left, withdrawing plunger I35from slot I34. The function of this lever I30 and plate I 3| is shownand described more in detail in said Patent No. 2,220,490.

In the patent the piston corresponding to I38 is actuated against aspring by the fluid which moves the wheel base forward, to projectplunger I35 into the connecting slot so'that the control lever cannot bemoved out of clampoperating position while the wheel is forward. Whenthe wheel ismoved back, the pressure on the piston is released and theplunger is withdrawn by said spring.

Start switch and circuits operated thereby Before initiating the feedmovement certain conditions exist in the electrical and hydrauliccircuits as a result of operation of start switch 280. Furthermore, withthe sizing device caliper in inoperative position, there is a completerestriction of air flow; and the resulting pressure causes the mercuryto close all four size contacts.

Closing start switch 280 completes a circuit through line 28I to oilpump relay 282, closing the contacts thereof and starting the oil pumpI50 and also slow feed oil pumps 300 and 30I. These pumps are all drivenby the same motor. At the same time, said switch opens a normally closedcircuit to CRI5 through contact 281 of CRI6.

When CRI5 is deenergized, current for all apparatus except the oil pumppasses through contact 4I8, closing contact 283 on oil pump relay 282(hereafter referred to as O. P.), and completes a circuit through lines284, 285, 420 and switch M to energize CRIB and open contact 281. Thus,the circuit to CRI 5 is also opened through said contact 281; and whenstart switch 288 is released to close the circuit through line 289 tocontact 281, said contact is open, and energization of CRI5 isprevented. l

Contact 283'through line 284 also acts through line 285 and normallyclosed contact 4| 5 of CRI 5 and line M9 to contact 405 of O. P. andthus holds 0. P. after release of switch 280.

Jet operated pressure switch.

Size control 1 Anair operated sizing device of the type shown 6: inco-pending application Serial No. 773,388, filed septemberdl, 1947, ismountedfor movement toward and from operative relation with the work. Itconsists of acaliper element 230 having two fixed feelers and onemovable fee-ler 23I. One end-of the movable feeler engages an air valve232 and controls the flow of air in accordanceowith change in thediameter of the work piece.

shown in Patent No. 2,220,470, granted November 5, 1940, except that inthis case there are four contacts instead of two. Rather than repeat thedrawing ofthe above-mentioned patent, we merelyindicate these contactsin the conventional manner in the wiring diagram and identify them bythe numerals 1, 2, 3 and 4. When the caliper 230 is in inoperativeposition, the movable feeler 23I, not being restrained by the surface ofa work piece, permits air valve 232 to move to a closed position. Airpressure is thus built up in the mercury switch (not shown), and allfour contacts remain closed until the caliper is placed on the work.Then feeler 231 is moved by contact with the work to open valve 232; andas the pressure drops, all four contacts are opened.

Time delay relay 335 energized through #4 sizing device contact holdsnormally closed contact 334 open for a predetermined interval and thusprevents a complete circuit to any of the other sizing'device contactsafter the caliper is returned to engagement with the work piece anduntil the sizing device contacts are opened by the mercury column. Ifthese contacts were not temporarily dead, 334 would permit a completecircuit from sizing device contact #3 which would operate the resetvalve and move the Wheel base to inoperative position instead ofcontinuing the feeding movement.

Movement of caliper 230 toward and from operative position is used toactuate a limit switch 235, the function of which will be describedlater.

Normally closedsizing device contacts While caliper 238 is out ofcontact with a work piece, air pressure'builds up in the mercury switchand closes all four contacts.

Contact #1 completes a circuit from L1 to one side of the slow feedsolenoid through line 330. Line 33I connects the other side of saidsolenoid through line 332 to normally closed contact 334 ofdelay relay335. i

Contact #2 "closes a circuit from L1 through. lines 340 and 34l to CR6and through lines 342, 33I and 332 to normally closed contact 334 ofdelay relay 335. Delay relay 335 is energized from contact #4. Thus,contact 334 remains open and CR6 and the slow feed solenoid remaindeenergized.

Line 340 from contact #2 leadsto a normally open contact 35I of CR1.Line 340 is also connected to CR9 through line 233. The other side ofCR9. is connected to L2 through line 234.

Contact #3 connects L1 through line 360 to CR1 and through lines 38I,33I and 332 to contact 334 of delayrelay 335. CR1 remains deenergizedbecause contact. 334 is open at this time.

Work: clamp and wheel feed interlock Before bringing the grinding wheelforward, the work must be held securely by the clamping fixtures. Solong as there is no pressure on the clamping fixtures, pressure switch380 has a normallyclosed contact 38I which completes a circuiteafrom L1through line .382,.-contact 3H and The change in air pressure is used tochange the level in a mercury U tube of the type i lines 383' and 364wei'xerg iz'e emu to; isenergized,- its normally closedcontact 310'opened; and the circuit through line. 312 togtne reset solenoidisbroken, deenergizihg" said sole noid and permitting spring 313' to shiftvalve 314 to the right. In this positionvalve 3"! directs fluid underpressure from lines W t and 3'95 through line 3M to the left end offeed: eon-trot Valve I53,- thus preventing the shifting of sa d valve toadvance wheel it While the work eianips are open.

Clamps hydrate-lie and electric circuits When valve; 395 is openedbylever [3 0, fluid under pressure from line 3'90' may pass through lines396 and 391 to the work clamping fixtures H and 12. Said fluid alsopassesfthrou gl'i line 398 to actuate pressure switch 3%. When soactu'ate'd said switch opens contact 381, deener: gizing" ems, closingcontact 3T0 and energizing the reset solenoid so that valve 314' movesto the left to connect line 391 withexhaust, thus relieving pressureatthe'front end of va'lve [.53. It also closes contact 33Which completesa circuit from L2 through line sssana manuauy opei'atedheadF stool;starting limit switch (not show ilto ener gize E? which starts motor350. has an additional normally open Contact 386 which is closed at thistime. Contact 3 connects L1 with one side of open contact 3'45 of CR6".

Hydraulic feed rapid Fluid under pressure is supplied to feedv cylinder'25 by a constant volume pump I 59- through lines. Hit and I52, reversingvalve 153 and line IE4 at a pressure determined by relief valve 155'.Fluid under pressure from relief valve I55 passes through line 56!} tovalve Nil at a; pressure deter mined byrelief valve F52 Saidvalve I6! ispressure operated from right to leftagainst? a spring Fluid underpressure from line l5 l is also directed throughline I7 to the slow feedsolenoid valve l-lrl and throughline N30 to valve l-6l=. Said valvethus-hastwo-sourcesof fluid under pressure at two different pressures.Fluid at either pressure is directed through line- ['82 to work: restsolenoid! valve 183. The'oniy-reason-for'the high pressure is to movethe work rest into position rapidly. The change to-low pressure reducesthe impact of the rest against the stop 82' or the work. The lowpressureis sufiicient to support! the work during. grinding.

Fluid from line [t passes through a restriction l-9i3= and through lineIM to a nozzle 192 from which. the fluid is discharged as ajet againstthe end of piston rod 21. When piston rod- 2! approaches nozzle l92closely enough to reduce the flow therefrom; the resulting pressure actsthrough line its to' actuate pressure operated switch 1-94.

Grinding feed Fluid" under pressure forthe pin grinding feed issuppl'ied' by" differential'pumps- 3% and 301', the capaeit'yof pumpSllifbein'g slightly greater than that of pump or it'may be of thesamecape-e: ity and operated. at a slightly higher speed;

Pump wills connected through lines 302 and 383 to one end orv feed:cylinder J'ancl through check-valve:fi'll l to line F54 forexliaust:Line 302 isconnected: by liner 305 to fast feed? valve'= 315 Pump: sun;is '--also connected through checlri valve 301% to the intake :of; pump"301-; When valve 315 is open to' exhaustt. that portion oi the output oft me 361- is conneeted through chaser/awe 3'0 1 The high pressure inline 31 0 noses cheekv'aw the so: that the entire output or pump'surpasses through un s are w iereit is addedto the en output of pump301' and passes through-cheo valve 3! $0 that the (L'Ofilliifiddliliblit (if 5617].).

When slow feed; valve l'H isshi'f-tedto exhaust position,- the entireoutput of pump 3!]! is exha'usted through lines 308; and 309-. Underthese conditions the only fluid under pressure remaining, to actuatepiston 52 is the sma-ll volume by which the output ofpumpsonexceedsthatof pump 301.

Master" stop swiich' and overload shut of The entire machine may bestopped with the w-heet base in inoperative position either by mas ter'stop" switch lflllor" by merited relays 4111*. For this purpose saidstep switch may be" con nected to L1 through any or all of threecircuits;

(a) From s't'op switch" Mt? through 1ines= 85, Elli contact 2 81 0110316normally closed contact of start switch 288-; contact" 505 650. P1, '1415 oontact 430'- of TEX, wheelbase limit switch 414", and contact 283o'fO; Pl lid-L11 (h) ere-m stop switch lllll" through line's"- 2'85;restaurant 283 of 0; PL to! I51. p

rom stop switch 400 threugh lines 2-85 eoiita'ct 415 of CR' IS, 06mm 430o'fTRK; we base lir'nitswitch 41 i line 2 84, and oontaet 2 83 of O. P.Li.

The wheel lease limit switch A l-'4" is closed" when the wheel basemoves forward and serves to hold 0 3- P. energized after operation ofeither" stop switch 300 or'overload fl l fi'to" keeptheoil pump I56operating until wheel base I5 moves to inoperative position, when saidswitch'is released and the ail pump' Stoops.

Closing stop switch 4% connects" L1 through of; the above-mentionedpathsthrough: line ll)! to energize CRl5;gopen-ing='contact 415 231111closing contacts 4-1;! 911113114181,

Opening overload relays 4 10 will 1 deener'gize GR,-|;6,-c1osing.normally closed '28! and counseling Li threugh normally 7 closed switch280, l lines 289 and-1401' to energize C'RrI-5.-

1' Opening normally closed 4 1% breaks? the" circuit to start switch280.- Closing- 411 holds CRITS through 283 of O. P and lines 284 and285. Closing 4I8 connects L1 froinontact 405 of 0*. P. throughline 406and from 41 8 through line 383 to energize CRIO which deenergizes resetsole noid, causing wheel base I to move to inoperative position" andopen switch 4I4.

Opening limit switch 4 I 4' serves to stop not only the oil pump I50 butalso all other motors on the machine, such as the work 350 and wheeldrive motors. Although the circuits for these motors are not shown, theyare similar to that for the oil pump. Regardlessof how many motors arestopped, the principal feature of the method of stopping lies in thefact that the oil pump I50 is kept in operation until thewheel hasbeenmoved away from the work and thus provides the motive power foreffecting the back off movement.

If for any reason the hydraulic system should fall through leakage orotherwise, the wheel base could not be moved to inoperative position andthe machine would keep running. In order to insure the shutting. off ofthe machine, a timing relay TRX is placed in parallel with CRIB and thecontact 430 of TRX in series with the wheel base limit switch 4I4. Saidrelaywill be energized simultaneously with CRI 5 and will function toopen the same circuit or limit switch H4 at a predetermined timethereafter.

Operation To initiate the feeding movement of grinding Wheel IS, theoperator shifts valve I53to the left by means of lever I56, thusdirecting fluid from line I52 through line I54to the right hand end ofcylinder 25. Piston 2B in said cylindermoves to the left, thus movingslide and wheel base I 5 rapidly to position grinding Wheel IS inoperative relation to one of the, crank pins on crankshaft 10. As wheelI6 reaches the portion of' the crank TI known as the cheek, the rapidmovement is reduced by dash pot 3| to a speed suitable for cheekgrinding. The feeding movement continues at this rate until the flow offluid from nozzle I92 is reduced or stopped by the end of piston rod 21.

When valve I53 moves to the left, line I5! is connected to the exhaustpassage from said valve. This line is connected through line I58 to theleft end of valve I6I. Line I5! is continued to the upper end ofcylinder I02 and through line 55 to the upper end of cylinder 50. LineI5! is connected directlyto the left end of feed cylinder 25.

When the upper end of cylinder I02 is connected to exhaust, thepressureon plate I20 is released and said plate, being then lifted by springs I2I, releases valve I which is then moved to closed position by springI28. mum underpressure' from line I40 due to restriction "I43 has beenacting through. line -I4I to hold piston I38 in the left hand position.With the closing of valv I26, fluid from restriction I43 builds uppressure in line I44 and against the head end of piston I38. Because ofthe greater surface at the head end, said piston is moved to the rightand plunger I blocks slot I34, lever I30 having been moved into slot I32to actuate the work clamping fixtures and start rotation thereofbeforethe initiation of said feeding movement.

Pressure built up in lines I91 and I93 as a result of blocking theescape of fluid from nozzle I92 actuates pressure switch I94 to closecontact I95 thereon andopen contact I96. Opening contact I96 opens acircuit through line I91 to relay coil CR4 which is held through contact25I of CR5, contact221 of CRI2 which depends on normally closed timercontact 2I0 and normally closed gauge limit switch contact 236. Thus,the p nin of contac I96 has no immediate effect on CR4.

Contact I95 directs current from line Ithrough line I98 and the normallyclosed contact 2I0iof timer clutch relay 2II to energize relay CRI2.Contact 22Iof said relay CRI2 then completes a circuit through line 222to start timer motor 223.

Contact 224 'of CRI2 completes a circuitfrom contact I95 on pressureswitch I94 throughlline 225, pin feed limit switch 60, line 226, contact240 of CR9 which'is energized through size device contact 2 so long asthe caliper 230 is in inoperative position. The circuit is completedthrough line 242 to relay CR5 opening contact 25I and closing contact252. Opening contact25l "removes one source ofenergizati'on to relaycoil CR4 through line 231 and holding circuit contact 260. However, theholding circuit is still completed from L1 through the normally closedcon tact 236 of gauge limit switch 235 and line 231 Said holding circuitis also maintained by the third contact 2210f CRI2. Said contact isconnected through line 228 toline 231. Thus, caliper 230 may be made toengage the work at any time; but opening contact 236 thereby will notdeenergize relay CR4 and the work rest solenoid until CRI2 isdeenergized, CR5 has been energized, andcurrentcut oif from all sourcesto relay CR4. I I

CRI2 is not deenergized until timer223 functions at the end of apredetermined period, be ginning with the actuation of jet operatedpressure switch I94.

Work rest Theopening of contact 236 by movement of thegauge limit switch235 in response to the positioning movement of caliper 230 willdeenergize relay CR4 if CRI2 is alreadydeenergized, openin the circuitfrom L1 through contact 25I and line 20I to dee'nergize the work restsolenoid. Spring I84 will then shift valve I83 to the right, connectingpressure line I 82 from valve I6I to line I85, leading to the lowerendof work rest cylinder I02, and moving piston IOI rapidly up wardly sothat work rest engaging memberf=95 may engage andshift work rest intooperative relation with work piece 10. It should be noted that fluidunder pressure for operating the work rest at this time comes to valveI6'I from pump I50 through high pressure line I5Iand line I80. Aspiston-I 0| moves upwardly, it uncovers a port leading to line I01 whichin turn is connected throughline I64 to-the right endof valve I5I. Saidvalve then movesto the left against spring I63 and changes the source offluid from high pressure lines I5I to. I80 to low pressure. line I60.Thus, the work rest is moved rapidly into position at high pressure andheld in, working. position by a lower pressure.

, Line, I01 also leads to the left end of ajslow feed by-pass valve I09,which will be described later in connection with, associated elements.

The aboveoperation .ofthe, work rest takes place only after theexpiration of the timed period. Prior to that time, contact 252 ofrelayCR5 completes another circuit from line. 242 through line 243 toenergize the fastfeed solenoid and shift valve 3| 5 to the left againstspring3I6. When fast feed valve 3I5 is in this position, it blocks theexhaust of fluid fromline. 305 and pumps 300 and 30I. Since pump 30I'isat this time receiving its supply from pump I 50-and lines 399 and 3H]as described above, check valve 306 isheld closed by the higherpressure; and

the'total output of the two pumps 300 and30l is directed to feedcylinder 50 to efiecta rough grindingfeed." This feed is for grindingthe 1 1 crank pins round. This feeding movement conti nues until ,cam-B2 011 handwheel .42 actuates limit switch 60. Opening one contact ofswitch. .60 deenergizes (3R5, closing 251 and opening 252 ,Gldsing theother contact of switch 5!] energizes the timer clutch to start thetimed pe iod.

Opening 252 deenergizes the fast feed solenoid, and valve H5 is shiftedto open line 3. .15 to exhaust thus lay-passing the output of pumps 330and to stop a rough feed movement of feed piston 52.

- Feed is resumed after the period for which. timer 223 is set, but onlyif caliper 23B, is in enag'ement with the work piece. Operation of thetimer'opens contact 2-10 and closes 212. Moving the-caliper intoengagement with the work opens contact 2-36 and closes; 238.

Opening timer contact 2H1 deenergizes C342 to stop the timer 223.Closing contact 2 I 2 closes a circuit from L1 through line I98 tocontact 238 of gauge limit switch 235.

Closing contact 238 energizes CR5 which closes 2512 o en r ize f st feedsolenoi a shift val e 31115 t c t off exhaust from l ne 30'5- .A: l rcus to CB4 are opened, including om sts 236 of au limit switch 235', 2.21.of CR and 251 of CR5.

Shift n va v 8- t the right utsoif the supply o h h pressur luid fr mlin 3.09 to pump 39.1.- u p .1 th n pump f om pu p .3110 through checkvalve 386 and from he pump through check valve 312 to line 303. Pump30!) pumps through line 302 an amount equal to the difference incapacity of the two'pumps. This provides, a second feed rate for arough-grinding operation for quick reduction to approximate finishedsize.

Feed continues at second rate until work size causes first contact ofthe sizing device to fume-:-

#1 sizing device contact energizes the slow feed solenoid to shift valveI'll to change line 309 from high pressure to exhaust so that the outputof pump 30! passes through check'valve 301- to exhaust, Ieaving only thesmall volume which is the difierence between the capacities of the twopumps to continue driving feed piston 52 at a third feed rate. Thisfeedjrate is for a finish grinding operation.

As the work is reduced in size, sizing device contact #2 energizes CR6throughlines 340 and 341 and CR9 through lines 340 and 233. CR6 is heldthrough contact 386 of CR5 opens 240 to deenergize Sizing device contact#2 also prepares a holding circuit for QB! when GR! is energized'bysizing device contact #3.

' 'W hen CR5 is deenergized, it opens contact 252 to deenergize the fastfeed valve 3I5 to exi rs Pum .0 and 3" to top he re d o ement of] piston52.'

After the feed movement stops, the grinding wheel remains in contactwith the work to effect a polishing operation which includes a slightadditional removal of stock, the extent of which is determi d by sizingdevice contact #3.

When sizing device contact #3 is closed, it energizes CR1 closingcontacts 351 and 3,52. l provides a holding circuit which includessizing device #2. 35 2 energizes CR|0- which completes circuitstonornially closed 38l of hydraulic clamp liznit switch 330,.

CRilll, when energized, opens contact 3-10 to deenergize the resetsolenoid. Spring 313 shifts valve 314 to connect high pressure line 393rrom 15! to 391 to shift valve I53 to reset position.

1 2 In this p s tion o valve 153:, fluid und r pressur i d rec ed toeficct a rev rsal. of feed pi s :25 and 52 and work rest piston IM toreturn them to starting position.

We claim:

1. A grinding machine including a bed, a work support and a grindingwheel support slidably mounted thereon for movement toward and from saidwork support, means for successively supporting .a series of spacedportions on a work piece during a grinding operation including aseparate stead v rest; for each portion, means for moving each of saidrests into operative position when the corresponding work portion is inposition to be ground, a calipering device movable toward and fromoperative position relative to the portion to be ground, and meansresponsive to movement of the calipering device into operative positionfor causing said moving means" to move the steady rest corresponding tothe portion being ground to move into work supporting position.

2. A grinding machine including a bed, a work support and a grindingwheel support slidably mounted thereon, a grinding wheel. rotatablymounted in said support, said Work support being slidably mounted formovement longitudinally relative to said grinding wheel, means on saidwork support: for successively supporting a series of spaced portions ona work piece including a separate steady rest for each portion and asingle hydraulic motor mounted on the bed substantially in alignmentwith: the grinding wheel for moving the proper. steady rest intooperative relation with the work.

3. A grinding machine including a bed, a work support and agrind-ingwheel support slidably mounted thereon, said work support being slidablymounted for movement longitudinally relative to said grinding wheel,means for successively supporting a series of spaced portions on a workpiece duringa grinding operation including a separate steady rest foreach port-ion, means for effecting saidlongitudinal movementintermittently to positionsaid portions in operative relationfwith saidgrinding wheel, and means including a common motor for causing thesteady rest corresponding to h POI-tion being ground to move into worksupporting position.

4. In a grinding machine, a bed, a grinding wheel support slidablymounted thereon, a Work support slidablymounted thereon, means to effecta relative longitudinal movement of said supports for successivelyplacing a series of axially spaced portions on a work piece in operative relation with said grinding wheel, a plu rality of steady restmembers on said work support in fixed axial relation to said spacedportions. and a single work rest actuating device in fixed a l re tionwi h a rin in wheel for actuating the rest corresponding to the workportion which is in operative relation with the grinding wheel.

5. In a grinding machine, a bed, a grinding wheel support slidablymounted thereon, a work support slidably mounted thereon forlongitudinal movement relative to said wheel support for successivelyplacing a series of axially spaced portions on a work piece in operativerelation with said grinding Wheel, a plurality of steady rest members onsaid work support in fixed axial relation to said Spaced portions andmeans to hold all of said rests in inoperative position .except the Onein front of the grinding wheel ineluding an obstruction in the path ofeach of said inoperative rests.

6. In a grinding machine, a bed, a grinding wheel support slidablymounted thereon, a work support slidably mounted thereon, means toeffeet a relative longitudinal movement of said supports forsuccessively placing a series of axially spaced portions 011 a workpiece in operative relation with said grinding wheel, a plurality ofsteady rest members on said work support in fixed axial relation to saidspaced portions and means to prevent movement of any of said restsexcept the one in front of the grinding wheel including a pair oflongitudinally fixed bars positioned to obstruct movement of said rests,said bars being longitudinally spaced to permit one a single actuatingmeans for steady rests, a timing mechanism and means for starting sameat a predetermined point in the grinding operation,

and means actuated by said timer for causing said actuating means tomove the steady rest corresponding to the portion being ground into worksupporting position.

8. A grinding machine including a bed, a work support and a grindingwheel support slidably mounted thereon for movement toward and from saidwork support, means on said work support for successively supporting aseries of spaced portions on a work piece during a grinding operationincluding a separate steady rest for each portion, a single actuatingmeans for said steady rests, a calipering device movable toward and fromoperative position relative to the portion to be ground, a timingmechanism and means for starting same at a predetermined point in thegrinding operation and means actuated by said timer in cooperation withthe movement of said calipering device, for causing said actuating meansto move the steady rest corresponding to the portion being ground intowork supporting position.

9. A grinding machine including a bed, a work support anda grindingwheel support slidably mounted thereon for movement toward and from saidwork support, means for successively supporting a series of spacedportions on a work piece during a grinding operation including aseparate steady rest for each portion, a calipering device movabletoward and from operative position relative tothe portion to be ground,a

timing mechanism and means for starting same at a predetermined point inthe grinding operation and means actuated by said timer in cooperationwith the movement of said calipering 'size position, power meansincluding a motor common to all supports for successively moving each ofsaid support members toward and from i its respective stop and means foradjusting each of said work engaging members separately to the finishedsize of the particular portion to be supported.

11. In a machine tool, a plurality of steady rests, one for each of aseries of spaced portions of a work piece, each rest comprising a basemember, a work engaging and supporting member movably mounted thereonfor movement toward and from operative position, a positive stop in thepath of movement of said work engaging member for locating said memberin finished size position, power means common to all supports for movingsaid support member in the direction of said stop, means to actuate saidpower means first with fluid under agiven pressure and means operable assaid rest engages the work to switch to a supply of fluid at a differentpressure.

12. In a grinding machine, a bed, a work support and a grinding wheelsupport slidably mounted thereon, work rests on said work support, awork rest actuating device on said bed, a work rest engaging member onsaid device out of contact with said work rest when retracted, means oneach of said rests for engagement by said member and means for effectingpositive engagement between said parts during withdrawal thereof fromwork supporting position.

13. In a metal working machine, a work support, means for clamping awork piece in said support, a cutting tool, movable toward and away fromsaidkwork support, power means for actuating said clamping means andsaid cutting tool, a main power supply for the machine, master controlmeans for stopping said machine including means for controlling thepower means for said cutting tool to move said tool to inoperativeposition, and additional control means actuated by said movement of saidcutting tool for delaying the stopping of said main power supply untilsaid tool is withdrawn.

l4.'In a metal working machine, a work support, means for clamping awork piece in said support, a cutting tool movable toward and away fromsaid work support, power means for actuating said cutting tool,additional power operated mechanisms in said machine including workdrive means, hydraulic pumps, and tool rotating means, a main powersupply for the machine,

master control means actuated either manually or under certainpredetermined conditions by any of said power operated mechanisms forstopping all of said mechanisms except said pump including means forcontrolling the power means for said cutting tool to move said tool toinoperative position, and additional control means actuated in responseto said movement of said cutting tool for cutting off said main powersupply.

15. In a metal working machine, a work carriage, means for rotatablysupporting a work piece thereon, a cutting tool movable toward and awayfrom said work support, power means for actuating said work supportingmeans and said cutting tool including a motor-driven pump and hydraulicmotor for said supporting means and said cutting tool, means including avalve operable upon failure of said work supporting means I to supportsaid work piece, to direct fluid tomove said cutting tool to inoperativeposition.

16. In a machine tool, a bed, a work support, a tool support and asteady rest all movably mounted on said bed, means for causing relativetransverse and longitudinal movements between saidwork support, and saidsteady rest and tool support, a control lever for said movements andmeans to prevent operation of said control lever to cause saidlongitudinal movement while said tool and said steady rest are inoperative position including a plunger for limiting the movement of saidlever, and means operable upon withdrawal of said steady rest forwithdrawing said plunger to inoperative position.

17. In a grinding machine, a work support, a Wheel support, a grindingwheel rotatably mounted thereon, means to effect relative transversemovement between said supports including a hydraulic motor and pumps forsupplying fluid under pressure for operating said motor, a back rest forsupporting a work piece during a grinding operation, means forperforming a part of said grinding operation without the back rest andmeans operable upon movement of said rest into operative position forchanging the rate of said transverse movement to a slower rate.

18. In a grinding machine, a work support, a wheel support, a grindingwheel rotatably mounted thereon, means to eiTect relative transversemovement between. said supports including a hydraulic motor and pumpsfor supplying fluid under pressure for operating said motor, a p1uralityof outlets from each of said pumps, check valves in some of saidoutlets, means for applying a higher pressure to hold said check valvesclosed and means operable in response to changein size of a work piecefor diverting said higher pressure and permitting iiuid to pass throughcertain of said check valves whereby to adjust the combined output ofsaid pumps.

19. A machine for grinding axially spaced portions on a work pieceincluding a bed, a work support slidably mounted on said bed, a grindingwheel support slidably mounted on said bed for movement toward and awayfrom said work support, means for effecting movement of said grindingwheel support toward said work support at a rapid rate, means forreducing said rapid movement to a movement suitable for effecting arough grinding operation, means separate from said rapid feed means foreitecting said movement at a slow feed rate, a timing mechanism, meansfor stopping said rough grinding movement of the wheel support andstarting said timer to permit a grinding operation without feed for apredetermined interval, a caliper device movable toward and fromoperative position relative to the portion to be ground, and meansactuated jointly by movement of said caliper and said timer to workengaging position at the end of said predetermined interval forinitiating operation of said slow feed means.

29. .A grinding machine including a bed, a work support and a grindingwheel support slidably mounted thereon for movement toward and from saidwork support, a oalipering device movable toward and from operativeposition relative to the portion to be ground, a timing mechanism andmeans for starting same at a predetermined point in the grindingoperation, and means actuated by said timer in cooperation with themovement of said calipering device into work engaging position forinitiating movement of said grinding wheel support.

21. In a metal working machine, a work support, a cutting tool movabletoward and away from said work support, power means for actuating saidcutting tool, additional power-operated means including a work drivemechanism and hydraulic pumps, a main power supply for the machine,master'control means actuated either manually or in response to failureof any of said power-operated mechanism to function properly forstopping said machine, including means for controlling the power meansfor said cutting tool to stop all of said power-operated mechanismsexcept said pump, said pump serving to supply fluid to move said tool toinoperative position, and additional control means actuated in responseto said movement of said cutting tool for stopping said pump.

22. In a crank grinding machine, a bed, a grinding wheel supportslidably mounted thereon, a grinding wheel rotatably mounted in saidsupport, means for effecting a rapid feeding movement of said grindingwheel support to place said grinding wheel in operative position, meansto reduce said rapid feeding movement to a feed suitable to grind theside walls of a crankpin, means operable at the end of the rapid feedmovement for initiating a slower feed movement for truing the crankpin,means for stopping said truing feed after a predetermined movement whilecontinuing the grinding operation until stress in the crank is relieved,a caliper mounted for movement toward and away from operative engagementwith the work, means for resuming said feeding movement after apredetermined interval and at a slower rate, providing said caliper hasbeen moved to operative position, means for effecting successivereductions in the feed rate in response to a change in size of the workuntil a predetermined size is reached which is just short of thefinished size, and means to continue the grinding operation without feeduntil finish size is reached.

23. In a grinding machine, a work support, a wheel support, a grindingwheel rotatably mounted thereon, means to eiTect relative transversemovement between said supports including a hydraulic motor anddifferential pumps for supplying fluid under pressure for operating saidmotor, a back rest movably mounted on the work support for supporting awork piece during a grindmg operation and a hydraulic motor for movingsaid rest, means for temporarily stopping said transverse movement ofsaid rest into operative position for changing the rate of saidtransverse movement to a slower rate including a pressure operatedvalve, actuated at a predetermined point in the movement of said backrest for changing the connections between said pumps and said hydraulicmotor.

24. In a grinding machine, a work support, a wheel support, a grindingwheel rotatably mounted thereon, means to efiect relative transversemovement between said supports including a hydraulic motor anddifierential pumps for supplymg fluid under pressure for operating saidmotor, a back rest movably mounted on the work support for supporting awork piece during a grinding operation and a hydraulic motor for movingsame, means for temporarily stopping said transverse movement with saidback rest in inoperatlve position, and means including a pressureoperated valve operable in response to movement of said rest intooperative position for changing the rate of said transverse movement toa slower rate, and connections between said valve and said back rest foractuating said valve to change the flow of fluid between said pumps andsaid hydraulic motor.

25. In a grinding machine, a work support, a wheel support, agrindingwheel rotatably mounted thereon, means for eiTecti-ng relativetransverse movement between said supports including a hydraulic motor,differential pumps for supply- References Cited in the file of thispatent ing fluid under pressure for operating said motor, UNITED STATESPATENTS a pressure operated valve for controlling the supply of fluidfrom said pumps to said motor, a back Number Name Date rest forsupporting the work piece during the 5 11045376 88. 3, 1 12 grindingoperation, a piston and cylinder for ac- 1,925,911 p 3 tuating said backrest and. means for actuating 11411596 Crompton Defl 1938 said pressureoperated valve at a, predetermined l Postma Ju y 193 point in themovement of said back rest, com- 2,297,604 JQhIISOII Sept 29, 1942prising a fluid. conduit connecting said back rest 10 2322327 9 et a1J1me 1943 cylinder and said valve, 2,375,737 sllven May 8, 1945 HAROLDE, BALSIGER, 2,419,133 Garside Apr. 15, 1947 RALPH E. PRICE.

